Scientists Make Brains Transparent to Get a Better Look Inside

The stunning video above illustrates a new way of looking at the brain. Scientists at at Stanford University have developed a method for making tissue almost completely transparent (see below). A series of chemical treatments replaces the fatty lipid membranes surrounding cells with an acrylamide mesh that keeps microscopic details intact without scattering light like lipid does. Neurotransmitters and other important molecules remain in place and can be visualized with a rainbow palette of fluorescent dyes.

A mouse brain before (left) and after treatment (right). Image: Kwanghun Chung and Karl Deisseroth, HHMI/Stanford University

Until now, neuroscientists typically had to cut a brain into ultra-thin slices to visualize such features. But that chops up one of the things they’re most interested in studying: the cable-like axons that carry signals from one part of the brain to another. The new method makes it possible to visualize these long-range connections as well as the fine-scale anatomy and molecular make up of neurons, the scientists report today in Nature.

Although they developed the method in mouse brains, the team shows that it works on human post-mortem brain tissue too. In the Nature paper, they describe abnormal neural connections in an autistic boy whose brain had been stored in formalin for more than 6 years.